/*
 * Copyright (c) 2011, 2012, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.element.plaf.aqua;

import javax.swing.*;
import javax.swing.plaf.ComponentUI;
import javax.swing.plaf.basic.BasicPopupMenuUI;
import java.awt.*;
import java.awt.event.MouseEvent;

public class AquaPopupMenuUI extends BasicPopupMenuUI {
	public static ComponentUI createUI(final JComponent x) {
		return new AquaPopupMenuUI();
	}

	public boolean isPopupTrigger(final MouseEvent e) {
		// Use the awt popup trigger code since this only runs on our OS!
		return e.isPopupTrigger();
	}

	@Override
	public void paint(final Graphics g, final JComponent c) {
		if (!(g instanceof Graphics2D)) {
			super.paint(g, c);
			return;
		}

		// if (!(PopupFactory.getSharedInstance() instanceof ScreenPopupFactory)) {
		// 	super.paint(g, c);
		// 	return;
		// }

		// round off and put back edges in a new Graphics
		final Graphics2D g2d = (Graphics2D) g.create();
		final Rectangle popupBounds = popupMenu.getBounds(); // NB: origin is still at 0,0
		paintRoundRect(g2d, popupBounds);
		clipEdges(g2d, popupBounds);
		g2d.dispose();

		// if any subsequent drawing occurs over these corners, the window is square again
		super.paint(g, c);
	}

	protected void paintRoundRect(final Graphics2D g2d, final Rectangle popupBounds) {
		// setup the graphics context to blast alpha for every primitive we draw
		g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
		g2d.setComposite(AlphaComposite.Clear);

		// draw the 3px round-rect line around the outer bounds of the window,
		// this gives the appearance of rounded corners
		g2d.setStroke(new BasicStroke(3.0f));
		g2d.drawRoundRect(-2, -2, popupBounds.width + 3, popupBounds.height + 3, 12, 12);
	}

	static final int OVERLAP_SLACK = 10;

	protected void clipEdges(final Graphics2D g2d, final Rectangle popupBounds) {
		final Component invoker = popupMenu.getInvoker();
		if (!(invoker instanceof JMenu)) return; // only point corners originating from menu items

		final Rectangle invokerBounds = invoker.getBounds();

		// only get location on screen when necessary
		invokerBounds.setLocation(invoker.getLocationOnScreen());
		popupBounds.setLocation(popupMenu.getLocationOnScreen());

		final Point invokerCenter = new Point((int) invokerBounds.getCenterX(), (int) invokerBounds.getCenterY());
		if (popupBounds.contains(invokerCenter)) {
			// invoker is "behind" the popup, no corners should be pointed
			return;
		}

		// blast opaque background over the corners we want to "put back"
		g2d.setComposite(AlphaComposite.SrcOver);
		g2d.setColor(popupMenu.getBackground());

		final Point popupCenter = new Point((int) popupBounds.getCenterX(), (int) popupBounds.getCenterY());
		final boolean invokerMidpointAbovePopupMidpoint = invokerCenter.y <= popupCenter.y;

		if (invokerBounds.x + invokerBounds.width < popupBounds.x + OVERLAP_SLACK) {
			// popup is far right of invoker
			if (invokerMidpointAbovePopupMidpoint) {
				// point upper left corner, most common case
				g2d.fillRect(-2, -2, 8, 8);
				return;
			}
			// point lower left corner
			g2d.fillRect(-2, popupBounds.height - 6, 8, 8);
			return;
		}

		if (popupBounds.x + popupBounds.width < invokerBounds.x + OVERLAP_SLACK) {
			// popup is far left of invoker
			if (invokerMidpointAbovePopupMidpoint) {
				// point upper right corner
				g2d.fillRect(popupBounds.width - 6, -2, 8, 8);
				return;
			}
			// point lower right corner
			g2d.fillRect(popupBounds.width - 6, popupBounds.height - 6, 8, 8);
			return;
		}

		// popup is neither "far right" or "far left" of it's invoker
		if (invokerBounds.y + invokerBounds.height < popupBounds.y + OVERLAP_SLACK) {
			// popup is "middle" below it's invoker,
			// this is probably the "connected" case where both upper corners should touch
			g2d.fillRect(-2, -2, popupBounds.width + 4, 8);
		}

		// if none of these cases match...don't make any corners pointed
	}
}
